Body Double for Neville Longbottom
An article in icBerkshire was on the young Thomas Davy who got the part as a double on an off-chance.  This was the short piece on him and what he had to say:

A SNAP decision to get out of the rain landed one teenager with a part in the latest Harry Potter film.
On the day the production company came scouting for doubles at Windsor Boys' School, Thomas Davy only went into the school hall to get out of the downpour.
Over a year later the 15-year-old has found himself mixing with stars of stage and screen as the double for Neville Longbottom. "I always really wanted to be an actor but never thought it would be a reality" he said. "It's brilliant."
After being measured and having his photo taken, Thomas was called back for an audition at Pinewood Studio. He impressed the director so much he was cast as the double for the bumbling Neville in Harry Potter and the Goblet of Fire.
The child stars in the film can only work four hours a day because of labour laws so doubles are used for back shots and positioning.
Thomas is already living most teenagers' dreams. "I have a trailer were I can play around and was sat next to Miranda Richardson in make-up the other day" he said.
The award winning actress is playing Daily Prophet journalist Rita Skeeter. The teenager, who lives with his family in Duncannon Crescent, Windsor, will now be dividing his time until around next May between school and film studios in Watford.
But he has vowed not to forget his roots if he hits the big time. "I love living in Windsor and would have a place by the Long Walk. I have this picture of walking down there in the Winter."